October 23 – November 21 · Water

Scorpio birthstones

Scorpio carries Topaz and Obsidian in the zodiac tradition.

Topaz

Composition Aluminium fluorosilicate (Al₂SiO₄(F,OH)₂)
Hardness · System 8 · Orthorhombic

Nearly all blue topaz on the market began as colourless stone, irradiated and heated to produce the colour.

Traditionally linked to confidence, clear intention and honest self-assessment.

Obsidian

Composition Volcanic glass — silica-rich lava cooled too fast to crystallise
Hardness · System 5–5.5 · Amorphous

Fractures to an edge only nanometres thick — sharper than surgical steel, and still used in some specialist scalpels.

Traditionally associated with protection, boundaries and honest self-examination.

Sign or month?

Scorpio runs October 23 – November 21, which crosses two calendar months — so the zodiac stone and the monthly birthstone may or may not agree depending on your exact date. Neither system overrules the other; the zodiac one is simply older.

Compare against the monthly chart →

← All zodiac birthstones

Two systems, one birth date

Scorpio spans 2 calendar months, so you have more than one birthstone

Zodiac stones Topaz, Obsidian
Months it covers October and November
Stones of those months Opal, Tourmaline, Topaz, Citrine
In both systems Topaz

October 23 – November 21 — so the sign opens in one month and closes in another. Why the two lists never line up →

The split is uneven: 9 days fall in October and 21 in November. So most people with this sign — 70% — are sold the November stone.

Obsidian appears in no month at all — one of just four such stones across the twelve signs.

October Opal, Tourmaline November Topaz, Citrine

The stones themselves

Stone Mohs Crystal system Main sources
Topaz 8 Orthorhombic Brazil, Nigeria, Pakistan
Obsidian 5–5.5 Amorphous Mexico, USA, Iceland

Obsidian is the softer at 5–5.5 on the Mohs scale — below 7, which means household dust scratches it, so it belongs in earrings or a pendant rather than an everyday ring. What the scale means →

Topaz

Aluminium fluorosilicate (Al₂SiO₄(F,OH)₂) Named after Topazios, a Red Sea island — which actually produced peridot, not topaz

Obsidian

Volcanic glass — silica-rich lava cooled too fast to crystallise Worked into blades across the ancient world; Aztec ritual knives were obsidian